Sudoku is easy to play and the rules are simple. Fill in the blanks so that each row, each column, and each of the nine 3x3 grids contain one instance of each of the numbers 1 through 9.

Sudoku #077 (Hard)

Sudoku #078 (Hard)

Additional Sudoku puzzles as well as the solution to these two puzzles can be found at the following web page: http://www.puzzles.ca/sudoku.html